FILE PHOTO: Police vehicles are seen outside the Manchester Arena, where U.S. singer Ariana Grande had been performing in Manchester, northern England, Britain, May 23, 2017.Jon Super

LONDON (Reuters) - British police believe that other people could have been involved in a suicide bomb attack in Manchester that killed 22 people at a pop concert in May, and further arrests could be made, Sky News reported on Thursday, citing local police.

"We do believe that there are other people potentially involved in this. We don't believe it's a large network, we do believe there may be other arrests in the future," Sky News quoted Russ Jackson, head of counter terrorism policing in the north west of England, as saying.

Manchester police were not immediately able to confirm the comments, which were made at a media briefing.